Perpendicularly magnetized spin-orbit magnetic device

ABSTRACT

A perpendicularly magnetized spin-orbit magnetic device including a heavy metal layer, a magnetic tunnel junction, a first antiferromagnetic layer, a first block layer and a first stray field applying layer is provided. The magnetic tunnel junction is disposed on the heavy metal layer. The first block layer is disposed between the magnetic tunnel junction and the first antiferromagnetic layer. The first stray field applying layer is disposed between the first antiferromagnetic layer and the first block layer. The magnetic tunnel junction comprises a free layer, a tunneling barrier layer, and pinned layer. The tunneling barrier layer is disposed on the free layer. The pinned layer is disposed on the tunneling barrier layer. A film plane area of the free layer is greater than a film plane area of the tunneling barrier layer and a film plane area of the pinned layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of and claims thepriority benefit of U.S. application Ser. No. 16/219,980, filed on Dec.14, 2018, now pending. The prior U.S. application Ser. No. 16/219,980 isa divisional application of and claims the priority benefit of U.S.application Ser. No. 15/358,157, filed on Nov. 22, 2016, now patented.The prior application Ser. No. 15/358,157 claims the priority benefit ofTaiwan application serial no. 105124742, filed on Aug. 4, 2016. Theentirety of each of the above-mentioned patent applications is herebyincorporated by reference herein and made a part of this specification.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The disclosure relates to a perpendicularly magnetized spin-orbitmagnetic device.

Description of Related Art

Magnetic random access memory (MRAM) has advantages of fast speed, lowpower consumption, high density, non-volatile, and has almost unlimitedread and write times, and is predicted as a mainstream of memoriescoming in the next generation. A main structure of a memory device inthe MRAM is a stacked structure formed by stacking a pinned layer ofthree-layer materials with ferromagnet/non-magnetic metal/ferromagnet, atunneling barrier layer and a free layer of a magnetic material. Suchstacked structure can be referred to as a magnetic tunnel junction (MTJ)device. Since a write current only flows through the selected MTJdevice, and magnetic switching is determined by an intensity of thewrite current and an intensity of an external magnetic field, it availsdecreasing the write current after the MTJ device is miniaturized, andeffects of simultaneously improving write selectivity and decreasing thewrite current are theoretically achieved.

The MTJ devices using a spin-orbit-torque (SOT) mechanism to implementread and write operations can be divided into in-plan MTJ devices andperpendicular MTJ devices. Compared to the in-plan MTJ device, theperpendicular MTJ device has a lower operating current, a higher devicedensity and better data storability. A perpendicular spin torquetransfer random access memory (pSTT-RAM) is regarded as a memory of thenew generation, which records digital information of 0 and 1 throughspin transfer switching, and takes the perpendicular MTJ as a mainmagnetic memory cell structure, which has good thermal stability, and anoperating current thereof is smaller compared with that of the othertype of the magnetic memory.

If the SOT mechanism is adopted to implement the MRAM structure, anoperating speed and write reliability can be further improved. Aswitching mechanism of the SOT in a perpendicular film plane magnetictorque is to introduce the write current to a heavy metal layer. Theheavy metal layer may produce a spin transfer torque (STT) based on aspin Hall effect and the external magnetic field. Moreover, the writecurrent may produce a Rashba torque (RT) after passing through aperpendicular electric field at a material interface and the externalmagnetic field. Since the STT and the RT are all perpendicular to adirection of the write current and parallel to the film plane, the twotorques are added to form the SOT. Therefore, if a magnetic field isapplied to the ferromagnetic material on the film plane that isperpendicular to the magnetic torque, the SOT is produced to switch themagnetic torque of the ferromagnetic layer to achieve an effect ofwriting the memory device. However, the above mechanism requires toadditionally input the write current and apply the external magneticfield. Manufacturers hope to simplify design complexity of an operationmechanism used for controlling the magnetic memory cell structure incase that the SOT mechanism is used as a mechanism for reading andwriting the magnetic memory cells.

SUMMARY OF THE DISCLOSURE

The disclosure provides a perpendicularly magnetized spin-orbit magneticdevice including a heavy metal layer, a magnetic tunnel junction, afirst antiferromagnetic layer, a first block layer and a first strayfield applying layer. The magnetic tunnel junction is disposed on theheavy metal layer. The first block layer is disposed between themagnetic tunnel junction and the first antiferromagnetic layer. Thefirst stray field applying layer is disposed between the firstantiferromagnetic layer and the first block layer. The magnetic tunneljunction comprises a free layer, a tunneling barrier layer, and pinnedlayer. The tunneling barrier layer is disposed on the free layer. Thepinned layer is disposed on the tunneling barrier layer. A film planearea of the free layer is greater than a film plane area of thetunneling barrier layer and a film plane area of the pinned layer.

In order to make the aforementioned and other features and advantages ofthe disclosure comprehensible, several exemplary embodiments accompaniedwith figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments of thedisclosure and, together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device.

FIG. 2 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a first embodiment ofthe disclosure.

FIG. 3 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a second embodimentof the disclosure.

FIG. 4A is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a third embodiment ofthe disclosure.

FIG. 4B is a simulation schematic diagram of a stray magnetic field ofthe perpendicularly magnetized spin-orbit magnetic device of FIG. 4A.

FIG. 5 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a fourth embodimentof the disclosure.

FIG. 6 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a fifth embodiment ofthe disclosure.

FIG. 7A is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a sixth embodiment ofthe disclosure.

FIG. 7B is a simulation schematic diagram of a stray magnetic field ofthe perpendicularly magnetized spin-orbit magnetic device of FIG. 7A.

FIG. 8 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a seventh embodimentof the disclosure.

FIG. 9 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to an eighth embodimentof the disclosure.

FIG. 10 is a simulation schematic diagram of a free layer and a firststray field applying layer implementing a stray magnetic field accordingto the second embodiment of the disclosure.

FIG. 11 is another simulation schematic diagram of a free layer and afirst stray field applying layer implementing a stray magnetic fieldaccording to the second embodiment of the disclosure.

FIG. 12 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a third embodiment ofthe disclosure.

FIG. 13 is another structure view of a of the perpendicularly magnetizedspin-orbit magnetic devices according to the third embodiment of thedisclosure.

FIG. 14 is the other structure view of the perpendicularly magnetizedspin-orbit magnetic devices according to the third embodiment of thedisclosure.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 100. The perpendicularlymagnetized spin-orbit magnetic device 100 mainly includes a magnetictunnel junction 110 and a heavy metal layer 150. In the presentembodiment, the magnetic tunnel junction 110 includes a pinned layer120, a tunneling barrier layer 130 and a free layer 140. The pinnedlayer 120 is, for example, a material stacking layer offerromagnet/non-magnetic metal/ferromagnet consisting of a lower pinnedlayer 126, a coupling layer 124 and an upper pinned layer 122. Amagnetic moment vector 123 of the upper pinned layer 122 and a magneticmoment vector 127 of the lower pinned layer 126 are opposite to eachother and perpendicular to a film plane to present a vertical couplingarrangement without being changed by an operating magnetic field orother factors.

The pinned layer 120 is disposed on the tunneling barrier layer 130. Thetunneling barrier layer 130 can be disposed on the free layer 140. Thefree layer 140 is a memory layer in the perpendicularly magnetizedspin-orbit magnetic device 100. The heavy metal layer 150 may receive aninput current Ic from an electrode contact of the perpendicularlymagnetized spin-orbit magnetic device 100. Moreover, the input currentIc may flow through the heavy metal layer 150 to produce a plurality ofspin currents with different directions due to a spin Hall effect (SHE),so as to produce a resultant moment together with an external magneticfield H, such that a magnetic moment of the free layer 140 is switchedto achieve a data read/write effect.

In order to facilitate description, coordinate axes X, Y, Z are set inthe figures of the embodiments of the disclosure to facilitatesubsequent description. An X-axis direction is an extending direction ofthe film plane, a Y-axis direction is an upward direction perpendicularto a paper surface, and a Z-axis direction is a direction perpendicularto the film plane. The film plane of each layer is parallel to an XYplane, and arrows 127, 141 used for representing magnetic momentdirections of magnetic moment vectors belong to the positive Z-axisdirection, and arrows 123, 142 belong to the negative Z-axis direction,and the others are deduced by analogy. In the present embodiment, aprovided direction of the external magnetic field H and a transferdirection of the input current Ic belong to the positive X-axisdirection.

The perpendicularly magnetized spin-orbit magnetic device 100 in FIG. 1still adopts the input current Ic input from external and the externalmagnetic field H in order to achieve the data read/write operation. Forexample, when the input current Ic is a positive value and the externalmagnetic field H is applied, a direction of a spin transfer torqueinduced by the free layer 140 is upward and perpendicular to the papersurface (i.e. the positive Y-axis direction), such that the direction ofthe magnetic moment in the free layer 140 is changed from the arrow 141into the arrow 142. Comparatively, when the input current Ic is anegative value (i.e. a flow direction of the input current Ic is areverse direction) and the external magnetic field H is applied, thedirection of the spin transfer torque induced by the free layer 140 isdownward and perpendicular to the paper surface (i.e. the negativeY-axis direction), such that the direction of the magnetic moment in thefree layer 140 is changed from the arrow 142 into the arrow 141.However, if the external magnetic field H is not applied, the spintransfer torque is not generated.

The embodiment of the disclosure provides a perpendicularly magnetizedspin-orbit magnetic device, in which an antiferromagnetic layer, a blocklayer and a stray field applying layer are additionally added togenerate a stray magnetic field, so as to produce a situation the samewith that of the external magnetic field to the free layer of themagnetic tunnel junction, and provide a magnetic moment switching effectto the perpendicularly magnetized spin-orbit magnetic device when theinput current is input. Embodiments are provided below to describe thespirit of the disclosure in detail, though the disclosure is not limitedto the provided embodiment, and the embodiments can also be suitablycombined.

FIG. 2 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 200 according to a firstembodiment of the disclosure. A material of the upper pinned layer 122and the lower pinned layer 126 in FIG. 2 can be a ferromagnetic materialwith perpendicular anisotropy. The upper pinned layer 122 and the lowerpinned layer 126 can be a single layer structure or a multi-layercomposite structure. The upper pinned layer 122 and the lower pinnedlayer 126 of the single layer structure are, for example, implemented byferromagnetic materials of ferrous (Fe), cobalt (Co), nickel (Ni),gadlinium (Gd), terbium (Tb), dysprosium (Dy), boron (B) etc., or analloy of the above elements (i.e., CoFeB, CoFe, NiFe . . . etc.). Ashape of the upper pinned layer 122 or the lower pinned layer 126 may bea round or an oval. The upper pinned layer 122 and the lower pinnedlayer 126 of the multi-layer composite structure can be a compositelayer structure of a ferromagnetic material and a metal material, forexample, a composite layer structure composed of elements such asCo/platinum (Pt), Co/Ni, Co/palladium (Pd), etc. A material of thecoupling layer 124 can be Ruthenium (Ru), and the thickness of thecoupling layer 124 can be 5 Å to 20 Å. The tunneling barrier layer 130is an insulating material having a magnetic tunnel condition under aspecified thickness. For example, a material of the tunneling barrierlayer 130 can be MgO. The insulating materials can be magnesium oxide,aluminium oxide, magnesium, or a combination thereof.

A material of the free layer 140 can be a ferromagnetic material withperpendicular anisotropy. The free layer 140 mainly implements the dataread/write operation through switching of the magnetic moment in themagnetic film layer, so that the ferromagnetic material of the freelayer 140 can be Fe, Co, Ni, Gd, Tb, Dy, B or an alloy of the aboveelements, for example, CoFeB, NF, FeB, etc. A thickness of the freelayer 140 can be 10 Å to 100 Å. The free layer 140 can be a single layerstructure or a multi-layer composite structure. If the free layer is acomposite structure formed by multi-layer ferromagnetic materials, thematerial of the multi-layer composite structure can be a compositestructure consisting of elements such as Co/Pt, Co/Ni, Co/Pd, etc. Themagnetic moment vector of the free layer 140 is arranged byperpendicular to the film plane. A material of the heavy metal layer 150can be a material generating a spin Hall effect and/or a quantum spinHall effect such as tantalum (Ta), platinum (Pt), tungsten (W), or acombination thereof. A thickness of the heavy metal layer 150 can be 20Å to 200 Å.

The perpendicularly magnetized spin-orbit magnetic device 200 of FIG. 2additionally has a first antiferromagnetic layer 230, a first strayfield applying layer 220 and a first block layer 210. The first strayfield applying layer 220 is disposed between the first antiferromagneticlayer 230 and the first block layer 210. The first antiferromagneticlayer 230 contacts the first stray field applying layer 220 to define adirection of a magnetic moment in the first stray field applying layer220 to be parallel to the film plane, as shown by arrows 231 and 232. Indetail, in order to ensure that the first antiferromagnetic layer 230may define the direction of the magnetic moment, the firstantiferromagnetic layer 230 is processed with a field annealingtreatment of a predetermined temperature, so as to use the firstantiferromagnetic layer 230 to fix the direction of the magnetic momentin the first stray field applying layer 220 (for example, the X-axismagnetic moment direction indicated by the arrow 221). The firstantiferromagnetic layer 230 can be composed of an antiferromagneticmaterial, and the antiferromagnetic material can be platinum-manganesealloy (PtMn), magnesium oxide (MnO), iridium-manganese alloy (IrMn),chromium oxide (CrO), or a combination thereof. A thickness of the firstantiferromagnetic layer 230 can be 50 Å to 200 Å.

In other words, the first stray field applying layer 220 is influencedby the first antiferromagnetic layer 230 (for example, the magneticmoment directions indicated by the arrows 231, 232) to produce a closedmagnetic circle parallel to the film plane and strayed outside the firststray field applying layer 220, so as to produce a stray magnetic fieldHs. In the present embodiment, the direction of the magnetic moment inthe first stray field applying layer 220 is shown as the arrow 221. Thefirst stray field applying layer 220 can be composed of a ferromagneticmaterial, and the ferromagnetic material can be Fe, Co, Ni, Gd, Tb, Dy,B or an alloy of the above elements. A thickness of the first strayfield applying layer 220 can be 30 Å to 3 kÅ. The first block layer 210is used for blocking the first antiferromagnetic layer 230 fromtransferring a magnetic moment arrangement direction, i.e. to avoid thecurrent Ic in the heavy metal layer 150 from being influenced by thefirst antiferromagnetic layer 230. On the other hand, since a spincurrent is produced in the heavy metal layer 150, the first block layer210 is required to block the spin current in the heavy metal layer 150from influencing the first stray field applying layer 220. The firstblock layer 210 may have a predetermined thickness obtained throughexperiments, so as to effectively block transferring of the spin currentbetween the metals or the ferromagnetic materials of the upper and lowerlayers, such that operation mechanisms of each layer can be pure withoutinfluencing each other. A material of the first block layer 210 can bemagnesium oxide, aluminium oxide, magnesium, or a combination thereof.

In this way, regarding the free layer 140, the function of the straymagnetic field Hs is the same with that of the external magnetic field Hof FIG. 1. In other words, to operate the perpendicularly magnetizedspin-orbit magnetic device 200, it is only required to provide the inputcurrent Ic to the heavy metal layer 150, and the free layer 140 mayimplement magnetic moment switching to generate the stray magnetic fieldHs, so as to implement the read/write function of the data memorized bythe free layer 140 without additionally providing the external magneticfield H. In this way, complexity of the perpendicularly magnetizedspin-orbit magnetic device 200 in the read/write operation issimplified.

In the embodiment of the disclosure, the first block layer 210, thefirst stray field applying layer 220 and the first antiferromagneticlayer 230 are disposed under the heavy metal layer 150. In the presentembodiment, the heavy metal layer 150 of FIG. 2 is disposed on the firstblock layer 210, the first block layer 210 is disposed on the firststray field applying layer 220, and the first stray field applying layer220 is disposed on the first antiferromagnetic layer 230. In otherembodiment complied with the spirit of the disclosure, the first blocklayer, the first stray field applying layer and the firstantiferromagnetic layer can also be disposed above the pinned layer 120of the magnetic tunnel junction 110. The first stray field applyinglayer referred in the embodiments of this specification can be called asan external filed layer.

It should be noted that in the embodiment of the disclosure, shapes ofthe magnetic tunnel junction 110 and the first stray field applyinglayer 220 in the perpendicularly magnetized spin-orbit magnetic device200 and areas of film planes are compared, and data simulation isperformed to the stray magnetic field to analyze a shape and an areaproportion between the free layer 140 of the magnetic tunnel junction110 and the magnetic tunnel junction 110 in order to obtain the betterstray magnetic field Hs, or being influenced by magnetic fields of otherdirections. Shapes of the magnetic tunnel junction 110, the heavy metallayer 150, the first block layer 210, the first stray field applyinglayer 220 or the first antiferromagnetic layer 230 can be rounds, ovals,squares or rectangles.

In the following description, it is assumed that the shapes of themagnetic tunnel junction 110, the heavy metal layer 150, the first blocklayer 210, the first stray field applying layer 220 and the firstantiferromagnetic layer 230 are all rounds, and the shapes of each layer(including the free layer 140) in the magnetic tunnel junction 110 arealso rounds. The heavy metal layer 150 has a first film plane area A1 onthe XY plane, and the magnetic tunnel junction 110 has a second filmplane area A2 on the XY plane. In the present embodiment, the first filmplane area A1 is greater than the second film plane area A2. The firststray field applying layer 220 and the first antiferromagnetic layer 230have a same third film plane area A3 on the XY plane. It should be notedthat regarding the free layer 140, a “horizontal direction straymagnetic field Hs” is a magnetic field component of the stray magneticfield Hs parallel to the film plane of the free layer 140 (i.e. parallelto the XY plane), and the horizontal direction stray magnetic field Hsmay effectively produce the spin transfer switching effect to the freelayer 140. A “vertical direction stray magnetic field Hs” is a magneticfield component of the stray magnetic field Hs perpendicular to the filmplane of the free layer 140 (i.e. parallel to the Z-axis direction). Thevertical direction stray magnetic field Hs is hard to produce the spintransfer switching effect to the free layer 140, but may interfere thespin transfer switching effect to make the transfer switching effectmuch worse. When the third film plane area A3 of the first stray fieldapplying layer 220 is the same with the second film plane area A2 of thefree layer 140, and the shapes thereof are consistent, throughsimulations of the stray magnetic field Hs in FIG. 2 to FIG. 5, it isknown that the horizontal direction stray magnetic field Hs at aboundary of the free layer 140 of FIG. 2 is larger than the horizontaldirection stray magnetic field Hs at the boundary of the free layer 140in FIG. 3, FIG. 4 and FIG. 5. However, the vertical direction straymagnetic field Hs at the boundary of the free layer 140 of FIG. 2 isalso larger than the vertical direction stray magnetic field Hs at theboundary of the free layer 140 in FIG. 3, FIG. 4 and FIG. 5.

FIG. 3 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 300 according to a secondembodiment of the disclosure. The first antiferromagnetic layer 330defines a direction of the magnetic moment in the first stray fieldapplying layer 320 to be parallel to the film plane, as shown by arrows231 and 232. The direction of the magnetic moment in the first strayfield applying layer 320 is indicated by the arrow 221. A differencebetween FIG. 2 and FIG. 3 is that the third film plane area A3 of thefirst antiferromagnetic layer 330 and the first stray field applyinglayer 320 is smaller than the first film plane area A1 of the heavymetal layer 150, and the third film plane area A3 is greater than thesecond film plane area A2 of the magnetic tunnel junction 110. A filmplane area of the first block layer 310 is A1. Through simulations ofthe stray magnetic field Hs in FIG. 2 to FIG. 5, it is known that thehorizontal direction stray magnetic field Hs and the vertical directionstray magnetic field Hs at the boundary of the free layer 140 of FIG. 3are all larger than the horizontal direction stray magnetic field Hs andthe vertical direction stray magnetic field Hs at the boundary of thefree layer 140 in FIG. 4 and FIG. 5, and are all smaller than thehorizontal direction stray magnetic field Hs and the vertical directionstray magnetic field Hs at the boundary of the free layer 140 in FIG. 2.

FIG. 4A is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 400 according to a thirdembodiment of the disclosure, and FIG. 4B is a simulation schematicdiagram of the stray magnetic field Hs of the perpendicularly magnetizedspin-orbit magnetic device 400 of FIG. 4A. The first antiferromagneticlayer 430 defines a direction of the magnetic moment in the first strayfield applying layer 420 to be parallel to the film plane, as shown byarrows 231 and 232. The direction of the magnetic moment in the firststray field applying layer 420 is indicated by the arrow 221. Adifference between FIG. 4A and FIG. 2, FIG. 3 is that the third filmplane area A3 of the first antiferromagnetic layer 430 and the firststray field applying layer 420 is equal to the first film plane area A1of the heavy metal layer 150. A film plane area of the first block layer410 is A1. Through simulation of the stray magnetic field Hs and FIG.4B, it is known that the horizontal direction stray magnetic field Hs (amagnetic field Hsx in FIG. 4B) sensed by the whole free layer 140 inFIG. 4B is more average, and a value of the vertical direction straymagnetic field Hs (a magnetic field Hsz in FIG. 4B) is smaller than thesimulation of FIG. 2 and FIG. 3. In detail, an average value of themagnetic field Hsx is smaller than the horizontal direction straymagnetic field Hs of the free layer 140 of FIG. 2 and FIG. 3, and isgreater than the horizontal direction stray magnetic field Hs of thefree layer 140 of FIG. 5. The average value of the magnetic field Hsz issmaller than the vertical direction stray magnetic field Hs of the freelayer 140 of FIG. 2 and FIG. 3, and is greater than the verticaldirection stray magnetic field Hs of the free layer 140 of FIG. 5.

FIG. 5 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 500 according to a fourthembodiment of the disclosure. A difference between FIG. 5 and FIG. 2,FIG. 3, FIG. 4 is that the third film plane area A3 of the firstantiferromagnetic layer 530 and the first stray field applying layer 520is greater than the first film plane area A1 of the heavy metal layer150. The first block layer 510 has the first film plane area A1. In thisway, through simulation of the stray magnetic field Hs, it is known thatthe horizontal direction stray magnetic field Hs sensed by the wholefree layer 140 in FIG. 5 is more average, and a value of the verticaldirection stray magnetic field Hs is smaller than the simulation of FIG.2, FIG. 3 and FIG. 4. In other words, an average value of the horizontaldirection stray magnetic field Hs of the free layer 140 of FIG. 5 issmaller than the horizontal direction stray magnetic field Hs of FIG. 2to FIG. 4, and an average value of the vertical direction stray magneticfield Hs of the free layer 140 of FIG. 5 is also smaller than thehorizontal direction stray magnetic field Hs of FIG. 2 to FIG. 4. Inthis way, based on the simulation of FIG. 2 to FIG. 5, in order to makethe free layer 140 to have the even horizontal direction stray magneticfield Hs and avoid obtaining a larger vertical direction stray magneticfield Hs, the film plane area of the first antiferromagnetic layer andthe first stray field applying layer is preferably to be greater than orequal to the film plane area of the heavy metal layer.

The first block layer, the first stray field applying layer and thefirst antiferromagnetic layer can also be disposed above the pinnedlayer 120 of the magnetic tunnel junction 110, and structures ofperpendicularly magnetized spin-orbit magnetic devices 600, 700, 800 ofFIG. 6 to FIG. 8 are taken as examples for description. FIG. 6 is across-sectional view of a structure of a perpendicularly magnetizedspin-orbit magnetic device 600 according to a fifth embodiment of thedisclosure. In the present embodiment, the first block layer 610 isdisposed on the pinned layer 120 of the magnetic tunnel junction 110.The first stray field applying layer 620 is disposed on the first blocklayer 610, and the first antiferromagnetic layer 630 is disposed on thefirst stray field applying layer 620. The first antiferromagnetic layer630 defines a direction of the magnetic moment in the first stray fieldapplying layer 620 to be parallel to the film plane (i.e. parallel tothe XY plane), as shown by arrows 631 and 632. An arrow 621 is used toindicate the direction of the magnetic moment in the first stray fieldapplying layer 620. Since the first stray field applying layer 620 islocated away from the heavy metal layer 150, the first block layer 610is not required to block the spin current in the heavy metal layer 150from influencing the first stray field applying layer 620. However, thefirst block layer 610 is still required to block the firstantiferromagnetic layer 630 from transferring the magnetic momentarrangement direction of the coupling layer 124 in the pinned layer 120.Functions and materials of the first block layer 610, the first strayfield applying layer 620 and the first antiferromagnetic layer 630 arethe same as that of the corresponding layers of FIG. 2.

In FIG. 6, the first stray field applying layer 620 and the firstantiferromagnetic layer 630 have the same film plane area A3. It isassumed that the first block layer 610 has the second film plane areaA2, and the third film plane area A3 of the first stray field applyinglayer 620 and the first antiferromagnetic layer 630 is smaller than thesecond film plane area A2 of the free layer 140. Through the simulationof the stray magnetic field Hs, it is known that a magnetic fieldreception of the free layer 140 of FIG. 6 is similar to the simulationof FIG. 2. In case of a more detailed comparison, the horizontaldirection stray magnetic field Hs at the boundary of the free layer 140of FIG. 2 is slightly greater than the horizontal direction straymagnetic field Hs at the boundary of the free layer 140 of FIG. 6, andthe vertical direction stray magnetic field Hs at the boundary of thefree layer 140 of FIG. 6 is slightly greater than the vertical directionstray magnetic field Hs at the boundary of the free layer 140 of FIG. 2.Namely, compared with the free layer 140 of FIG. 6, the free layer 140of FIG. 2 may effectively implement the spin transfer switching effect,and may slightly decrease the influence of the vertical direction straymagnetic field Hs.

FIG. 7A is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 700 according to a sixthembodiment of the disclosure, and FIG. 7B is a simulation schematicdiagram of the stray magnetic field Hs of the perpendicularly magnetizedspin-orbit magnetic device 700 of FIG. 7A. The first antiferromagneticlayer 730 defines a direction of the magnetic moment in the first strayfield applying layer 720 to be parallel to the film plane, as shown byarrows 631 and 632. The direction of the magnetic moment in the firststray field applying layer 720 is indicated by the arrow 621. Adifference between FIG. 6 and FIG. 7A is that the third film plane areaA3 of the first antiferromagnetic layer 730 and the first stray fieldapplying layer 720 is equal to the second film plane area A2 of themagnetic tunnel junction 110. The first block layer 710 has the secondfilm plane area A2. The stray magnetic field Hs sensed by the free layer140 of FIG. 7A may refer to the simulation waveform of FIG. 7B. Throughsimulations of the stray magnetic field Hs in FIG. 6 to FIG. 8 and FIG.7B, it is known that the horizontal direction stray magnetic field Hs (amagnetic field Hsx in FIG. 7B) sensed by the whole free layer 140 inFIG. 7B is more average. In detail, the horizontal direction straymagnetic field Hs and the vertical direction stray magnetic field Hs atthe boundary of the free layer 140 of FIG. 7B are all greater than thehorizontal direction stray magnetic field Hs and the vertical directionstray magnetic field Hs at the boundary of the free layer 140 of FIG. 6,and are smaller than the horizontal direction stray magnetic field Hsand the vertical direction stray magnetic field Hs at the boundary ofthe free layer 140 of FIG. 8.

FIG. 8 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 800 according to a seventhembodiment of the disclosure. The first antiferromagnetic layer 830defines a direction of the magnetic moment in the first stray fieldapplying layer 820 to be parallel to the film plane, as shown by arrows631 and 632. The direction of the magnetic moment in the first strayfield applying layer 820 is indicated by the arrow 621. A differencebetween FIG. 6 and FIG. 8 is that the third film plane area A3 of thefirst antiferromagnetic layer 830 and the first stray field applyinglayer 820 is greater than the second film plane area A2 of the magnetictunnel junction 110. The first block layer 810 has the second film planearea A2. Through simulation of the stray magnetic field Hs, it is knownthat the magnetic field sensed by the free layer 140 of FIG. 8 issimilar to the simulation of FIG. 5. Namely, the horizontal directionstray magnetic field Hs sensed by the whole free layer 140 in FIG. 8 ismore average and weaker compared to the horizontal direction straymagnetic field Hs of the free layer 140 in FIG. 6, FIG. 7, and thevertical direction stray magnetic field Hs of the free layer 140 in FIG.8 is relatively less compared to the vertical direction stray magneticfield Hs of the free layer 140 in FIG. 6, FIG. 7. In this way, based onthe simulation of the stray magnetic field Hs of FIG. 6 to FIG. 8, inorder to make the free layer 140 to have the even horizontal directionstray magnetic field Hs and avoid obtaining a larger vertical directionstray magnetic field Hs, the film plane area of the firstantiferromagnetic layer and the first stray field applying layer ispreferably to be greater than or equal to the film plane area of thepinned layer 120.

In the embodiment of the disclosure, the block layer, the stray fieldapplying layer and the antiferromagnetic layer can also be disposedunder the heavy metal layer 150 and above the pinned layer 120 of FIG.1, so as to strengthen an intensity of the stray magnetic field in thefree layer 140. Even more, if sizes of the upper and lower stray fieldapplying layers are properly adjusted, the vertical direction straymagnetic fields generated by the two stray field applying layers areprobably counteracted, so as to decrease a chance of interfering thefree layer 140.

FIG. 9 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device 900 according to an eighthembodiment of the disclosure. In FIG. 9, the heavy metal layer 150 isdisposed on the first block layer 910, the first block layer 910 isdisposed on the first stray field applying layer 920, and the firststray field applying layer 920 is disposed on the firstantiferromagnetic layer 930. The first antiferromagnetic layer 930defines a direction of the magnetic moment in the first stray fieldapplying layer 920 to be parallel to the film plane, as shown by arrows231 and 232. The direction of the magnetic moment in the first strayfield applying layer 920 is indicated by an arrow 221. A second blocklayer 912 is disposed on the pinned layer 120 of the magnetic tunneljunction 110, a second stray field applying layer 922 is disposed on thesecond block layer 912, and a second antiferromagnetic layer 932 isdisposed on the second stray field applying layer 922. The secondantiferromagnetic layer 932 defines a direction of the magnetic momentin the second stray field applying layer 922 to be parallel to the filmplane, as shown by arrows 631 and 632. The direction of the magneticmoment in the second stray field applying layer 922 is indicated by anarrow 621. In this way, a magnetic intensity of a horizontal directionstray magnetic field Hs1 generated by the first stray field applyinglayer 920 is added with a magnetic intensity of a horizontal directionstray magnetic field Hs2 generated by the second stray field applyinglayer 922 in the horizontal direction, such that the free layer 140 mayobtain the strongest intensity of the horizontal direction straymagnetic field Hs sensed by the free layer 140 in FIG. 2 to FIG. 9.Comparatively, since the vertical direction stray magnetic field Hs1 andthe vertical direction stray magnetic field Hs2 are opposite to eachother, the two vertical direction stray magnetic fields Hs1 and Hs2 areslightly counteracted at the free layer 140 of FIG. 9. Namely, a valueof the vertical direction stray magnetic field parallel to the Z-axisdirection at the free layer 140 is decreased, so as to decrease a chanceof interfering the free layer 140 when the free layer 140 implements thespin transfer switching effect.

In an embodiment of the disclosure, it is also deeply analysed whetherthe shape of the stray field applying layer and the shape of the freelayer are interfered with each other to influence the stray magneticfield sensed by the free layer. FIG. 10 is a simulation schematicdiagram of the free layer 140 and the first stray field applying layer220 implementing the stray magnetic field Hs according to the secondembodiment of the disclosure. For simplicity's sake, only a left part ofFIG. 10 illustrates the free layer 140 and the first stray fieldapplying layer 220 located below the heavy metal layer, and an upperright part of FIG. 10 illustrates an intensity simulation diagram of thehorizontal direction stray magnetic field Hsx generated by the firststray field applying layer 220, and a lower right part of FIG. 10illustrates an intensity simulation diagram of the vertical directionstray magnetic field Hsz generated by the first stray field applyinglayer 220. It is assumed that the shapes of the free layer 140 and thefirst stray field applying layer 220 are all rounds, a diameter of thefree layer 140 is 300 nm, and a distance between the free layer 140 andthe first stray field applying layer 220 is 5 nm. In the intensitysimulation diagram of the horizontal direction stray magnetic field Hsx,a line L1 x/a line L2 x/a line L3 x respectively represent thehorizontal direction stray magnetic fields Hsx generated when thediameter of the first stray field applying layer 220 is respectively 200nm/300 nm/400 nm. In the intensity simulation diagram of the verticaldirection stray magnetic field Hsz, a line L1 z/a line L2 z/a line L3 zrespectively represent the vertical direction stray magnetic fields Hszgenerated when the diameter of the first stray field applying layer 220is respectively 200 nm/300 nm/400 nm. According to the simulationdiagram of FIG. 10, it is known that the smaller the diameter of thefirst stray field applying layer 220 is, the larger the horizontaldirection stray magnetic field Hsx at the boundary of the free layer 140is, and the larger the interference of the vertical direction straymagnetic field Hsz is. Comparatively, the larger the diameter of thefirst stray field applying layer 220 is, the smaller the horizontaldirection stray magnetic field Hsx at the boundary of the free layer 140is, and the smaller the interference of the vertical direction straymagnetic field Hsz is.

FIG. 11 is another simulation schematic diagram of the free layer 140and the first stray field applying layer 220 implementing the straymagnetic field Hs according to the second embodiment of the disclosure.Similar to FIG. 10, only a left part of FIG. 11 illustrates the freelayer 140 and the first stray field applying layer 220 located below theheavy metal layer, and an upper right part and a lower right part ofFIG. 11 respectively illustrate an intensity simulation diagram of thehorizontal direction stray magnetic field Hsx and an intensitysimulation diagram of the vertical direction stray magnetic field Hszgenerated by the first stray field applying layer 220. A differencebetween FIG. 10 and FIG. 11 is that the shape of the free layer 140 is around, though the shape of the first stray field applying layer 220 is asquare. In the intensity simulation diagram of the horizontal directionstray magnetic field Hsx, a line L1 x/a line L2 x/a line L3 xrespectively represent the horizontal direction stray magnetic fieldsHsx generated when a side length of the first stray field applying layer220 is respectively 200 nm/300 nm/400 nm. In the intensity simulationdiagram of the vertical direction stray magnetic field Hsz, a line L1z/a line L2 z/a line L3 z respectively represent the vertical directionstray magnetic fields Hsz generated when the side length of the firststray field applying layer 220 is respectively 200 nm/300 nm/400 nm.Similar to FIG. 10, according to the simulation diagram of FIG. 11, itis known that the smaller the side length of the first stray fieldapplying layer 220 is, the larger the horizontal direction straymagnetic field Hsx at the boundary of the free layer 140 is, and thelarger the interference of the vertical direction stray magnetic fieldHsz is. Comparatively, the larger the side length of the first strayfield applying layer 220 is, the smaller the horizontal direction straymagnetic field Hsx at the boundary of the free layer 140 is, and thesmaller the interference of the vertical direction stray magnetic fieldHsz is.

FIG. 12 is a cross-sectional view of a structure of a perpendicularlymagnetized spin-orbit magnetic device according to a ninth embodiment ofthe disclosure. The perpendicularly magnetized spin-orbit magneticdevice 1000 in FIG. 12 mainly includes an upper electrode 1260, a coverlayer 1270, a magnetic tunnel junction 1210, the heavy metal layer 150,a first block layer 1210, a first stray field applying layer 1220 and afirst antiferromagnetic layer 1230. The magnetic tunnel junction 1210includes the pinned layer 120, the tunneling barrier layer 130 and afree layer 1240. The upper electrode 1260 can be a bit line or beenconnected to the bit line. The heavy metal layer 150 can be a word lineor been connected to the word line. The pinned layer 120 is, forexample, a material stacking layer of ferromagnet/non-magneticmetal/ferromagnet consisting of the lower pinned layer 126, the couplinglayer 124 and the upper pinned layer 122. Functions and materials of theabove layers are the same as that of the corresponding layers in thesecond embodiment of FIG. 3. A material of the upper electrode 1260 canbe copper (Cu), aluminium (Ai), tantalum (Ta), . . . etc. or an alloy ofthe above elements. A thickness of the upper electrode 1260 can be 1 kÅto 6 kÅ. The cover layer 1270 can be composed of an non-magneticmaterial such as Ta, titanium (Ti) . . . etc. or an alloy of the aboveelements. A thickness of the cover layer 1270 can be less than 1 kÅ.

A difference between FIG. 3 and FIG. 12 of the embodiments is that afilm plane area A1240 of the free layer 1240 is larger than the secondfilm plane area A2 of the lower pinned layer 126. In detail, in order toavoid imperfections in part of the semiconductor process (e.g., aetching process), the residue remaining of the free layer 1240 in thesemiconductor process may cross the heavy metal layer 150 and the lowerpinned layer 126, thereby causing the heavy metal layer 150 and thelower pinned layer 126 to be shorted to each other. Therefore, the thirdembodiment is designed such that the film plane area A1240 of the freelayer 1240 is larger than the second film plane area A2 of the lowerfixed layer 126, so that the residue remaining of the free layer 1240 inthe free layer 1240 does not come into contact with the heavy metallayer 150. Thereby, the heavy metal layer 150 and the lower fixed layer126 is prevented from being short to each other. In the ninth embodimentof FIG. 12, the film plane area A1240 of the free layer 1240 is alsogreater than the second film plane area A2 of the lower pinned layer126, the coupling layer 124, the upper pinned layer 122 and/or atunneling barrier layer 130. From another point of view, a distance Lbetween the boundary of the second film plane area A2 of the lowerpinned layer 126 and the boundary of the film plane area A1240 of thefree layer 1240 is designed to more than 0.1 μm and less than 1.0 μm.

If the film plane area A1240 of the free layer 1240 is too large, thefree layer 1240 will require a larger driving current to perform thespin-orbit-torque (SOT) mechanism. In order to prevent the film planearea A1240 of the free layer 1240 from being excessively large andaffecting the magnetic inversion characteristics of the perpendicularlymagnetized spin-orbit magnetic device 1000, it is designed to make thefilm plane area A1240 of the free layer 1240 smaller than the third filmplane area A3 of the heavy metal layer 150 in the ninth embodiment. Inother embodiments of the disclosure, it may not limited the relationshipbetween the film plane area A1240 of the free layer 1240 and the thirdfilm plane area A3 of the first stray field applying layer 1220. Inother words, the film plane area A1240 of the free layer 1240 maygreater than the third film plane area A3 of the first stray fieldapplying layer 1220, although it may require the larger driving currentto perform the SOT mechanism.

FIG. 13 is another structure view of a of the perpendicularly magnetizedspin-orbit magnetic devices according to the ninth embodiment of thedisclosure. It includes four upper electrodes 1260 in strip shapeextending in the Y-axis direction, twelve (3 times 4) perpendicularlymagnetized spin-orbit magnetic devices (e.g., an element region 1001,which is framed here by a dashed line, presents a partial structure ofone of the perpendicularly magnetized spin-orbit magnetic devices),three heavy metal layers 150 in strip shape extending in the X-axisdirection, and a layer 1310 carrying the above elements in the ninthembodiment of FIG. 13. The layer 1310 includes the first stray fieldapplying layer 1220 and the first antiferromagnetic layer 1230. A shapeof the free layer 1240 is a round or an oval in FIG. 13; a shape of eachlayer in the pinned layer 120 and a shape of the tunneling barrier layer130 are also a round or an oval. The film plane area A1240 of the freelayer 1240 is larger than the second film plane area A2 of the lowerpinned layer 126. In other words, the first stray field applying layercan cover a plurality of perpendicularly magnetized spin-orbit magneticdevices (e.g., twelve (3 times 4) perpendicularly magnetized spin-orbitmagnetic devices in FIG. 13).

FIG. 14 is the other structure view of the perpendicularly magnetizedspin-orbit magnetic devices according to the ninth embodiment of thedisclosure. A difference between FIG. 2 and FIG. 3 is that a shape ofeach of layers 1410 of FIG. 14 is different from the shape of the layer1310 of FIG. 13. Each of the four layers 1410 is composed of the firststray field applying layer 1220 and the first antiferromagnetic layer1230, and the shape of each of the four layers 1410 is a strip shapestructure extending in the Y-axis direction (that is, extending alongthe bit line). That is, the extending direction of the firstantiferromagnetic layer 1230 is perpendicular to the extending directionof the heavy metal layer 150, and the first antiferromagnetic layer 1230is disposed corresponding to the upper electrode 1260 (e.g., the bitline).

In summary, the perpendicularly magnetized spin-orbit magnetic deviceprovided by the embodiments of the disclosure may spontaneously producea stray closed magnetic circle to the free layer in the magnetic tunneljunction to provide the stray magnetic field through theantiferromagnetic layer, the block layer and the stray field applyinglayer, so as to provide a switching effect to a magnetic moment in thememory cell structure when an input current is input as that does of anexternal magnetic field. In this way, operation complexity of theperpendicularly magnetized spin-orbit magnetic device is simplified.Since the perpendicularly magnetized spin-orbit magnetic device itselfmay produce the stray magnetic field without using the external magneticfield, and magnetic moment switching of the free layer of the magnetictunnel junction in the perpendicularly magnetized spin-orbit magneticdevice can be implemented only by introducing the input current, thedesign complexity of the operation mechanism used for controlling theperpendicularly magnetized spin-orbit magnetic device can be greatlysimplified.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of thedisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the disclosure covermodifications and variations of this disclosure provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A perpendicularly magnetized spin-orbit magneticdevice, comprising: a heavy metal layer; a magnetic tunnel junction,disposed on the heavy metal layer; a first antiferromagnetic layer; afirst block layer, disposed between the magnetic tunnel junction and thefirst antiferromagnetic layer; and a first stray field applying layer,disposed between the first antiferromagnetic layer and the first blocklayer, and providing a stray magnetic field parallel to a film plane,wherein the magnetic tunnel junction comprises: a free layer; atunneling barrier layer, disposed on the free layer; and a pinned layer,disposed on the tunneling barrier layer, wherein a film plane area ofthe free layer is greater than a film plane area of the tunnelingbarrier layer and a film plane area of the pinned layer.
 2. Theperpendicularly magnetized spin-orbit magnetic device as claimed inclaim 1, wherein the film plane area of the free layer is smaller than afilm plane area of the heavy metal layer, and the film plane area of thefree layer is smaller than a film plane area of the first block layer.3. The perpendicularly magnetized spin-orbit magnetic device as claimedin claim 2, and the film plane area of the free layer is smaller than afilm plane area of the first antiferromagnetic layer, and the film planearea of the free layer is smaller than a film plane area of the firststray field applying layer.
 4. The perpendicularly magnetized spin-orbitmagnetic device as claimed in claim 3, wherein the film plane area ofthe heavy metal layer is the same as the film plane area of the firstblock layer, the film plane area of the first antiferromagnetic layer isthe same as the film plane area of the first stray field applying layer.5. The perpendicularly magnetized spin-orbit magnetic device as claimedin claim 4, wherein the film plane area of the heavy metal layer is thesame as the film plane area of the first antiferromagnetic layer.
 6. Theperpendicularly magnetized spin-orbit magnetic device as claimed inclaim 4, wherein the film plane area of the heavy metal layer is largerthan the film plane area of the first antiferromagnetic layer.
 7. Theperpendicularly magnetized spin-orbit magnetic device as claimed inclaim 1, a distance between a boundary of the film plane area of thelower pinned layer and a boundary of the film plane area of the freelayer is more than 0.1 μm and less than 1.0 μm.
 8. The perpendicularlymagnetized spin-orbit magnetic device as claimed in claim 1, a shape ofthe first antiferromagnetic layer is a strip shape structure extendingin a direction of the bit line, an extending direction of the firstantiferromagnetic layer is perpendicular to an extending direction ofthe heavy metal layer, and the first antiferromagnetic layer is disposedcorresponding to the bit line.